Lobular Carcinoma in situ of the Breast

Carolyn Vachani, MSN, RN, AOCN
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 18, 2009

Dear OncoLink "Ask the Experts,"
I have been diagnosed with lobular carcinoma in situ (LCIS). I can find no information on this and I am very confused. Can you give me any information? Your help would be greatly appreciated.

Carolyn Vachani RN, MSN, AOCN, OncoLink's Nurse Educator, responds:

Lobular carcinoma in situ (LCIS) of the breast is not an actual "cancer", but rather a marker for the possibility of developing a cancerous condition in the future. LCIS is not associated with an abnormality on a mammogram, and is usually found “accidentally” during a biopsy of another abnormality. Studies have found that LCIS often goes undetected, and therefore the actual numbers of cases are unknown. It is mostly seen in younger women, with about 90% of cases seen in premenopausal women.

Experts believe that a woman with LCIS has a 7 to 12 times greater chance of developing breast cancer (in either breast) than a woman without LCIS. The treatment for LCIS has been debated over the years, ranging from biopsy with close follow up to bilateral mastectomy. Treatment decisions should take into account other risk factors and the patient's desires and anxiety. Women with LCIS should be followed closely with annual mammograms.

Tamoxifen was found to reduce the risk of subsequent breast cancer in these women. The STAR trial found that raloxifene worked as well as tamoxifen in reducing breast cancer risk. STAR found that both drugs reduced a woman’s risk of developing invasive breast cancer by 50%, but raloxifene resulted in 36% fewer uterine cancers and 29% fewer blood clots in participants. The study included postmenopausal women at high risk. These therapies may be an option for women with a history of LCIS.